trait_selection: fix assumptions-on-binders diagnostics - #158588
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Some changes occurred to the core trait solver cc @rust-lang/initiative-trait-system-refactor |
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r? BoxyUwU We intend to fully rework the way these diagnostics work and the errors are currently intentionally bad as they don't even have span information (they point to the whole containing function). I think keeping the status quo is preferable as a very explicit "this is still very WIP" and would personally prefer to close this PR |
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thanks, that makes sense. i was mostly looking at this as remove the placeholder text, but imo you're right that the nicer message is a bit misleading if the span is still basically wrong. i'll wait for boxyuwu's opinion before closing the pr. if i poke at this again later, i think i'd rather start by carrying more of the failed outlives predicate / binder info through first, then make the diagnostic nicer once it has enough data to not lie. |
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I think I agree with lcnr here 👍 Would you be interested in trying to do a more involved refactor here and figure out properly spanned diagnostics for -Zassumptions-on-binders? i.e. make it so we aren't just pointing to the whole item which the constraint originates from. I think this would be really useful to have done and I won't get the time to do it for a while because of other priorities (getting std/core to compile and then custom test suite). |
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Of course! |
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sick :3 it's probably a more involved change than your previous PRs so it's probably worth us chatting on zulip about it as you're working on it ✨ I would probably start by looking into where the spans for normal region errors come from (i.e. without -Zassumptions-on-binders) and then look into how to replicate that for -Zassumptions-on-binders |
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Reminder, once the PR becomes ready for a review, use |
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Keep rust-lang#158588 focused on reporting solver region constraints. The type-op behavior and its borrowck coverage now live in rust-lang#161423.
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Keep this branch focused on reporting solver region constraints. The type-op behavior and its borrowck coverage are handled separately.
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@bors r+ sick thanks, once your other PR lands we can come back and re-add the test that you previously had added |
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…tions_binders_diagnostics, r=BoxyUwU trait_selection: fix assumptions-on-binders diagnostics fixes rust-lang#157732 `-Zassumptions-on-binders` was losing the origin of solver region constraints. By the time regionck or borrowck reported them, every constraint received the containing item span, so diagnostics pointed at an entire function or const. Some paths were also still emitting placeholder text (`:3` and `meoow :c`). This keeps canonical solver responses and `ExternalConstraintsData` span-free, so source locations do not participate in candidate equality or caching. When a response is applied, `EvalCtxt::origin_span` is attached to each atomic solver `RegionConstraint` stored in `InferCtxt`. Late region conversion then uses the span attached to each constraint, including for ambiguity diagnostics. The affected paths now report `higher-ranked lifetime bound could not be satisfied` at the type use that introduced the failing constraint. UI coverage checks the rust-lang#157732 call-site diagnostic and the existing regionck alias-outlives case. Unit coverage checks that the spanned evaluator stays in semantic parity with the type-ir evaluator and preserves the first ambiguity origin span. The type-op behavior I ran into while working on this is split into rust-lang#161423. Future work: carry the failed outlives predicate or originating binder far enough through this path to name the exact bound that failed, rather than only pointing at its origin.
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…tions_binders_diagnostics, r=BoxyUwU trait_selection: fix assumptions-on-binders diagnostics fixes rust-lang#157732 `-Zassumptions-on-binders` was losing the origin of solver region constraints. By the time regionck or borrowck reported them, every constraint received the containing item span, so diagnostics pointed at an entire function or const. Some paths were also still emitting placeholder text (`:3` and `meoow :c`). This keeps canonical solver responses and `ExternalConstraintsData` span-free, so source locations do not participate in candidate equality or caching. When a response is applied, `EvalCtxt::origin_span` is attached to each atomic solver `RegionConstraint` stored in `InferCtxt`. Late region conversion then uses the span attached to each constraint, including for ambiguity diagnostics. The affected paths now report `higher-ranked lifetime bound could not be satisfied` at the type use that introduced the failing constraint. UI coverage checks the rust-lang#157732 call-site diagnostic and the existing regionck alias-outlives case. Unit coverage checks that the spanned evaluator stays in semantic parity with the type-ir evaluator and preserves the first ambiguity origin span. The type-op behavior I ran into while working on this is split into rust-lang#161423. Future work: carry the failed outlives predicate or originating binder far enough through this path to name the exact bound that failed, rather than only pointing at its origin.
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…tions_binders_diagnostics, r=BoxyUwU trait_selection: fix assumptions-on-binders diagnostics fixes rust-lang#157732 `-Zassumptions-on-binders` was losing the origin of solver region constraints. By the time regionck or borrowck reported them, every constraint received the containing item span, so diagnostics pointed at an entire function or const. Some paths were also still emitting placeholder text (`:3` and `meoow :c`). This keeps canonical solver responses and `ExternalConstraintsData` span-free, so source locations do not participate in candidate equality or caching. When a response is applied, `EvalCtxt::origin_span` is attached to each atomic solver `RegionConstraint` stored in `InferCtxt`. Late region conversion then uses the span attached to each constraint, including for ambiguity diagnostics. The affected paths now report `higher-ranked lifetime bound could not be satisfied` at the type use that introduced the failing constraint. UI coverage checks the rust-lang#157732 call-site diagnostic and the existing regionck alias-outlives case. Unit coverage checks that the spanned evaluator stays in semantic parity with the type-ir evaluator and preserves the first ambiguity origin span. The type-op behavior I ran into while working on this is split into rust-lang#161423. Future work: carry the failed outlives predicate or originating binder far enough through this path to name the exact bound that failed, rather than only pointing at its origin.
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…tions_binders_diagnostics, r=BoxyUwU trait_selection: fix assumptions-on-binders diagnostics fixes rust-lang#157732 `-Zassumptions-on-binders` was losing the origin of solver region constraints. By the time regionck or borrowck reported them, every constraint received the containing item span, so diagnostics pointed at an entire function or const. Some paths were also still emitting placeholder text (`:3` and `meoow :c`). This keeps canonical solver responses and `ExternalConstraintsData` span-free, so source locations do not participate in candidate equality or caching. When a response is applied, `EvalCtxt::origin_span` is attached to each atomic solver `RegionConstraint` stored in `InferCtxt`. Late region conversion then uses the span attached to each constraint, including for ambiguity diagnostics. The affected paths now report `higher-ranked lifetime bound could not be satisfied` at the type use that introduced the failing constraint. UI coverage checks the rust-lang#157732 call-site diagnostic and the existing regionck alias-outlives case. Unit coverage checks that the spanned evaluator stays in semantic parity with the type-ir evaluator and preserves the first ambiguity origin span. The type-op behavior I ran into while working on this is split into rust-lang#161423. Future work: carry the failed outlives predicate or originating binder far enough through this path to name the exact bound that failed, rather than only pointing at its origin.
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…uwer Rollup of 18 pull requests Successful merges: - #151061 (Build rustc and codegen backends with -Zembed-metadata=no) - #157949 (Allow self in const generics) - #158588 (trait_selection: fix assumptions-on-binders diagnostics) - #159954 (core: implement float conversion methods) - #160136 (Add `Default` implementation for `std::sync::Once`) - #160835 (resolver diagnostics: don't swallow labels and point out similar items as a note, not a label) - #161048 (Improve the ABI between the panic runtime and libstd) - #161292 (Add safety comments in alloc::Wtf8) - #161444 (Add some `rustc_type_ir` comments) - #161465 (Remove leftover immediate creation) - #152433 (Use `symlink_dir` to create junctions on Windows instead of trying to use symbolic links in `copy_link_internal`) - #159098 (Add Arc/Rc::strong_count_from_raw) - #159282 (Update documentation for `-Zdump-dep-graph`) - #161401 (Remove fields from TypeKind: Bool, Char, Float and Int) - #161431 (bootstrap: (offload) be stricter about selected compiler and paths) - #161451 (Avoid arming the Windows TLS destructor guard in fibers) - #161463 (Add myself to mailmap) - #161476 (Use bitset for locals_with_use_data) Failed merges: - #161443 (add internal DSL for testing binders)
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…tions_binders_diagnostics, r=BoxyUwU trait_selection: fix assumptions-on-binders diagnostics fixes rust-lang#157732 `-Zassumptions-on-binders` was losing the origin of solver region constraints. By the time regionck or borrowck reported them, every constraint received the containing item span, so diagnostics pointed at an entire function or const. Some paths were also still emitting placeholder text (`:3` and `meoow :c`). This keeps canonical solver responses and `ExternalConstraintsData` span-free, so source locations do not participate in candidate equality or caching. When a response is applied, `EvalCtxt::origin_span` is attached to each atomic solver `RegionConstraint` stored in `InferCtxt`. Late region conversion then uses the span attached to each constraint, including for ambiguity diagnostics. The affected paths now report `higher-ranked lifetime bound could not be satisfied` at the type use that introduced the failing constraint. UI coverage checks the rust-lang#157732 call-site diagnostic and the existing regionck alias-outlives case. Unit coverage checks that the spanned evaluator stays in semantic parity with the type-ir evaluator and preserves the first ambiguity origin span. The type-op behavior I ran into while working on this is split into rust-lang#161423. Future work: carry the failed outlives predicate or originating binder far enough through this path to name the exact bound that failed, rather than only pointing at its origin.
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…tions_binders_diagnostics, r=BoxyUwU trait_selection: fix assumptions-on-binders diagnostics fixes rust-lang#157732 `-Zassumptions-on-binders` was losing the origin of solver region constraints. By the time regionck or borrowck reported them, every constraint received the containing item span, so diagnostics pointed at an entire function or const. Some paths were also still emitting placeholder text (`:3` and `meoow :c`). This keeps canonical solver responses and `ExternalConstraintsData` span-free, so source locations do not participate in candidate equality or caching. When a response is applied, `EvalCtxt::origin_span` is attached to each atomic solver `RegionConstraint` stored in `InferCtxt`. Late region conversion then uses the span attached to each constraint, including for ambiguity diagnostics. The affected paths now report `higher-ranked lifetime bound could not be satisfied` at the type use that introduced the failing constraint. UI coverage checks the rust-lang#157732 call-site diagnostic and the existing regionck alias-outlives case. Unit coverage checks that the spanned evaluator stays in semantic parity with the type-ir evaluator and preserves the first ambiguity origin span. The type-op behavior I ran into while working on this is split into rust-lang#161423. Future work: carry the failed outlives predicate or originating binder far enough through this path to name the exact bound that failed, rather than only pointing at its origin.
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…tions_binders_diagnostics, r=BoxyUwU trait_selection: fix assumptions-on-binders diagnostics fixes rust-lang#157732 `-Zassumptions-on-binders` was losing the origin of solver region constraints. By the time regionck or borrowck reported them, every constraint received the containing item span, so diagnostics pointed at an entire function or const. Some paths were also still emitting placeholder text (`:3` and `meoow :c`). This keeps canonical solver responses and `ExternalConstraintsData` span-free, so source locations do not participate in candidate equality or caching. When a response is applied, `EvalCtxt::origin_span` is attached to each atomic solver `RegionConstraint` stored in `InferCtxt`. Late region conversion then uses the span attached to each constraint, including for ambiguity diagnostics. The affected paths now report `higher-ranked lifetime bound could not be satisfied` at the type use that introduced the failing constraint. UI coverage checks the rust-lang#157732 call-site diagnostic and the existing regionck alias-outlives case. Unit coverage checks that the spanned evaluator stays in semantic parity with the type-ir evaluator and preserves the first ambiguity origin span. The type-op behavior I ran into while working on this is split into rust-lang#161423. Future work: carry the failed outlives predicate or originating binder far enough through this path to name the exact bound that failed, rather than only pointing at its origin.
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…uwer Rollup of 19 pull requests Successful merges: - #151061 (Build rustc and codegen backends with -Zembed-metadata=no) - #154992 (Error on projection of dyn noncompat type in old trait solver) - #157949 (Allow self in const generics) - #158588 (trait_selection: fix assumptions-on-binders diagnostics) - #159954 (core: implement float conversion methods) - #160136 (Add `Default` implementation for `std::sync::Once`) - #160835 (resolver diagnostics: don't swallow labels and point out similar items as a note, not a label) - #161048 (Improve the ABI between the panic runtime and libstd) - #161292 (Add safety comments in alloc::Wtf8) - #161444 (Add some `rustc_type_ir` comments) - #161465 (Remove leftover immediate creation) - #159098 (Add Arc/Rc::strong_count_from_raw) - #159282 (Update documentation for `-Zdump-dep-graph`) - #161401 (Remove fields from TypeKind: Bool, Char, Float and Int) - #161431 (bootstrap: (offload) be stricter about selected compiler and paths) - #161451 (Avoid arming the Windows TLS destructor guard in fibers) - #161463 (Add myself to mailmap) - #161476 (Use bitset for locals_with_use_data) - #161483 (Warn about running ui-fulldeps tests in stage 1) Failed merges: - #161443 (add internal DSL for testing binders)
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Rollup merge of #158588 - Dnreikronos:trait_selection/assumptions_binders_diagnostics, r=BoxyUwU trait_selection: fix assumptions-on-binders diagnostics fixes #157732 `-Zassumptions-on-binders` was losing the origin of solver region constraints. By the time regionck or borrowck reported them, every constraint received the containing item span, so diagnostics pointed at an entire function or const. Some paths were also still emitting placeholder text (`:3` and `meoow :c`). This keeps canonical solver responses and `ExternalConstraintsData` span-free, so source locations do not participate in candidate equality or caching. When a response is applied, `EvalCtxt::origin_span` is attached to each atomic solver `RegionConstraint` stored in `InferCtxt`. Late region conversion then uses the span attached to each constraint, including for ambiguity diagnostics. The affected paths now report `higher-ranked lifetime bound could not be satisfied` at the type use that introduced the failing constraint. UI coverage checks the #157732 call-site diagnostic and the existing regionck alias-outlives case. Unit coverage checks that the spanned evaluator stays in semantic parity with the type-ir evaluator and preserves the first ambiguity origin span. The type-op behavior I ran into while working on this is split into #161423. Future work: carry the failed outlives predicate or originating binder far enough through this path to name the exact bound that failed, rather than only pointing at its origin.
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fixes #157732
-Zassumptions-on-binderswas losing the origin of solver region constraints. By the time regionck or borrowck reported them, every constraint received the containing item span, so diagnostics pointed at an entire function or const. Some paths were also still emitting placeholder text (:3andmeoow :c).This keeps canonical solver responses and
ExternalConstraintsDataspan-free, so source locations do not participate in candidate equality or caching. When a response is applied,EvalCtxt::origin_spanis attached to each atomic solverRegionConstraintstored inInferCtxt. Late region conversion then uses the span attached to each constraint, including for ambiguity diagnostics.The affected paths now report
higher-ranked lifetime bound could not be satisfiedat the type use that introduced the failing constraint. UI coverage checks the #157732 call-site diagnostic and the existing regionck alias-outlives case. Unit coverage checks that the spanned evaluator stays in semantic parity with the type-ir evaluator and preserves the first ambiguity origin span.The type-op behavior I ran into while working on this is split into #161423.
Future work: carry the failed outlives predicate or originating binder far enough through this path to name the exact bound that failed, rather than only pointing at its origin.